Manifolds.

What’s the difference in these two please?
Why has one got a smaller flange, and the other has ‘pipes’?

 

Beetle and van .
One has a servo and bigger carb , care to hazard a guess ??

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Thanks. The one for the servo is off of my van with no servo. I had the other one from when I got that 1303 beetle engine, as a spare. The engine came with a newish empi carb with the same size flange.
Can I fit that carb and manifold, if I change the jets on the carb, as that manifold looks ‘tidier?

 

You will be strangling it with a smaller choke, so it will be slower, plus empi carbs are over snottys fence material.

Original manifold with a solex 34 pict 3 is what you want.

 

No. Fit the one for your current carb.

 

Fit the biggest carburettor you have - the correct 34PICT-3 that produces correct vacuum for a bus.
The stock carbs are all designed to be smaller than the engine can cope with, its why a progressive livens up the engine even more as it has the equivalent of a 48mm single carburettor barrel. Then the exhaust gets in the way.

You need the manifold with the manifold vacuum takeoff for doing your air cleaner hot air feed properly too. Unless you like flat spots on cold days.

And when you fit it, you will find that the bolt in the servo takeoff pipe is over the back behind the mass of wires on the distributor cap anyway.

 

Thanks.
The pipes were never connected to anything on my oil Bath filter, as there is nowhere to connect to.
Do where does it connect to?
Or is it for a different filter?

 

If you have a Beetle oil bath filter, these can have a mechanical operated flap for hot vs cold air.

A proper Bay Window air cleaner, either oil bath or paper cartridge type, will have a vacuum operated flap that warms up the air for idling on cold days then switches to "cold" air for power at wider throttle . and this is driven from the manifold via a thermostat vacuum valve on top of the air cleaner.

It helps speed up warm-up, and prevent flat spots and idling to a halt with a frozen carb manifold on a cold day..

 

Just put back the original manifold and carb , BECAUSE IT WORKED - not exactly rocket science to work that one out is it ??



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...

 

And if you by any chance don't run it in cold winters ...then maybe not worry .

 

It actually diverts warm air until the engine’s warmed up, then the thermostat shuts it off. Engines don’t like breathing hot air: it reduces their efficiency. Nothing to do with revs or throttle setting.

 

Because the manifold vacuum collapses to zero when the throttle is wide open, the flap automatically drops to cold when you open the throttle, even if the intake air temperature is below 30C at idle which is the closing point for the vacuum thermo valve..

So its always trying for about 30C at idle, and cold air at WOT. The only time it doesnt try to feed hot air is when the intake temperature goes over 30C, or the vacuum drops as the throttle plate opens.

Its cleverer than you think, and why they moved on from wax capsules operating that flap.

As I have sawn off my intake on the air cleaner, its easier to see it in operation - I shall take a video..

 

Just checking on the available options to me.
THIS is rocket science.

 

I suppose the thin pipes on that are about 1/4 inch diameter . All hand made by craftsmen in the 1960's . I wonder how many of them owned a brand new Splitty.

 

isn't the vacuum pipe connected to the carb ? I've spent the last 18months collecting all the bits to do this I'm still not convinced it cured the flat spot

 

Not sure but I do know the thigh bone connected to the knee bone, surely we can all
agree on this.

 

With maybe one exception....

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On some carburettors, there is a vacuum takeoff that goes down to the base plate of the carb, where it sits on manifold, so it sucks vacuum with the throttle plate closed . That one works with the vacuum flap on the air cleaner.

Then another usual takeoff for the distributor that has no vacuum at idle for the timing advance.


On my old setup, the takeoff for the air cleaner vacuum flap was a small spigot on the manifold . With my progressive's different manifold, I had to drill and fit a spigot to the manifold for the vacuum takeoff.

One thing that happens is the little thermo vacuum switch on the air cleaner decides to either leak or gets blocked up. Then the flap never gets vacuum.

 

mines a pic-34 so bottom of the carb, I also managed to get a new thermo valve as the second hand ones I'd collected never worked.